5.2 b: Application
194
YASKAWA ELECTRIC
SIEP C710636 02B YASKAWA U1000 Technical Manual
This method can be used for a single induction motor connected to a drive. Do not use this method if the motor is one or
more frame size smaller than the drive, at motor speeds above 200 Hz, or when using a single drive to operate more than
one motor.
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Speed Estimation Speed Search 2 (b3-24 = 3)
Speed Estimation Speed Search 2 is used in V/f w/PG control mode.
The Speed Search estimates the motor rotation direction while the motor is coasting and then restarts operation. The
drive controls motor speed by using PG feedback. After the Speed Search is completed, the speed is accelerated or
decelerated to the frequency reference.
b3-14 sets how the drive determines the motor rotation direction when performing the Speed Search as follows:
• The drive uses the frequency reference to determine the direction of motor rotation in order to restart the motor.
• The drive detects the motor rotation direction in order to restart the motor.
Notes on Using Speed Estimation Speed Search
• Rotational Auto-Tuning for V/f Control (T1-01 = 3) needs to be first performed if you plan to use Speed Estimation in
V/f Control. Perform Stationary Auto-Tuning for Line-to-Line Resistance (T1-01 = 2) again if the there is a change in
the cable length between the drive and motor.
• Use Current Detection Speed Search 2 to search for speeds beyond 200 Hz, if the application is running multiple
motors from the same drive, or if the motor is considerably smaller than the capacity of the drive.
• Speed Estimation may have trouble finding the actual speed if the motor cable is very long. Current Detection Speed
Search 2 should be used in such situations.
• Use Current Detection Speed Search 2 instead of Speed Estimation when operating motors smaller than 1.5 kW. Speed
Estimation can end up stopping smaller motors, as it might not be able to detect the speed or rotation direction of such
small motors.
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Speed Search Activation
Speed Search can be activated as described below. Select the Speed Search type in parameter b3-24 independent of the
activation method.
1. Automatically activate Speed Search with every Run command. Set b3-01, Speed Search Selection at Start, to 1
(Enabled). External Speed Search commands are ignored.
2. Activate Speed Search using the digital input terminals.
The following input functions for H1-
can be used.
Table 5.7 Speed Search Activation by Digital Inputs
To activate Speed Search by a digital input, the input must always be set together with the Run command, or the Run
command must be entered after the Speed Search command is given.
3. After automatic fault restart
When the number of maximum fault restarts in parameter L5-01 is set higher than 0, the drive will automatically
perform Speed Search as specified by b3-24 following a fault.
4. After momentary power loss
This mode requires that the Power Loss Ride-Thru function be enabled always or at least enabled during CPU
operation (L2-01 = 1 or 2).
Refer to L2-01: Momentary Power Loss Operation Selection on page 301
5. After external baseblock is released
The drive will resume the operation starting with Speed Search if the Run command is present and the output
frequency is above the minimum frequency when the Baseblock command is released.
Setting
Description
b3-24 = 1, 3
b3-24 = 2, 4
61
External Search Command 1
Activate Speed Estimation Speed Search
Closed: Activate Current Detection Speed Search from the
maximum output frequency (E1-04).
62
External Search Command 2
Closed: Activate Current Detection Speed Search from the
frequency reference.
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